Institutions such as hospitals and nursing homes must serve palatable meals comprising both hot and cold foods to large numbers of persons in widely dispersed remote locations. Often, such institutions must serve these meals long after the meals are prepared and assembled. Accordingly, such institutions require means for storing and transporting pre-prepared meals to remote locations in a manner that preserves the safety and palatability of the foods, and also permits hot foods to be served hot and cold foods to be served cold.
Various types of food storage and transportation systems are known for delivering foods that are prepared in a central food preparation facility to remote food service locations. Several of these known food delivery systems include means for refrigerating and/or rethermalizing pre-prepared foods. These systems generally are of two types. A first type of system includes a stand-alone storage and transportation cart that includes an onboard refrigeration system for chilling at least a portion of the foods in the cart, and/or an onboard rethermalization system for heating at least a portion of the foods in the cart. One such system and cart is described in U.S. Pat. No. 6,073,547 to Westbrooks, Jr. et al. Typically, such a system includes a refrigeration unit for circulating chilled air in at least a portion of the cart. When such a system includes a rethermalization system, heat is supplied to foods in the cart either by a plurality of distributed heating elements, or by circulating heated air in at least a portion of the cart. Such self-contained food delivery carts are costly, require frequent servicing, and their large size and weight makes such carts difficult to transport and maneuver.
A second type of system includes a portable storage and transportation cart, and a separate supply unit or docking station for refrigerating and/or reheating foods in the cart. Typically in such systems, the cart is mated with the docking station when cooling and/or heating is required in the cart. Once the cart is docked in the docking station, chilled air is supplied from the docking station's refrigeration system to at least a portion of the cart through a cold air inlet in the cart. When the system includes a convective rethermalization system, heated air is supplied from the docking station's heating system to at least a portion of the cart through a hot air inlet in the cart. A system of the type having a separate cart and docking station for refrigerating and heating foods in the cart is described in U.S. Pat. No. 5,655,595 to Westbrooks, Jr.
One shortcoming of known institutional refrigeration and rethermalization systems of either type described above is their inability to provide uniform convective cooling and/or heating to all foods within the cart. As cold air is circulated in such units, the cold air naturally tends to migrate to lower portions of the cart, thereby failing to provide a desired rate of cooling to foods located in upper portions of the cart. Similarly, heated air tends to rise to upper portions of the cart, thereby failing to provide a desired rate of heating to foods located in lower portions of the cart. In addition, the hot and cold air currents in such systems typically have velocities that are too low to provide efficient and uniform convective heating and cooling. Still further, such systems often permit heated and/or chilled air to bypass or circumvent desired flow paths in the systems. Such deviant air flows further contribute to the inefficiencies and lack of uniform heating and cooling in such systems.
Accordingly, there is a need for a refrigeration/rethermalization food delivery system that provides substantially uniform heating and cooling of a large quantity of food portions. In addition, there is a need for a refrigeration/rethermalization system that provides substantially uniform convective air currents that optimize system efficiency and uniformity.